Outboard motors powered by internal combustion engines generally include a lubricating system with an oil reservoir. The motor comprises a cowling in which the engine is positioned, and a lower unit extending downwardly from the cowling to a water propulsion unit, such as a propeller.
The engine is generally oriented so that a crankshaft thereof extends vertically. The crankshaft is arranged in driving relation with a drive shaft which extends through the lower unit to a transmission connected to the propeller.
So that gravity may be used to aid a return flow of lubricant from the engine to the reservoir, the oil reservoir is positioned below the engine. Due to the limited space within the cowling, the oil reservoir is generally positioned within the lower unit.
The oil reservoir commonly comprises a tank element which is connected to the bottom side of the engine or a plate element connected to the bottom of the engine with one or more bolts or similar connectors. A supply pipe leads from the tank through the guide to an oil pump, and a return pipe or passage leads through the guide to the tank.
This arrangement suffers from several disadvantages. One problem is that oil often leaks at the connection between the oil tank and the engine wall or plate into the remainder of the motor. This is often the case even when a gasket is positioned between the mating surface of the engine or guide and tank.
Also, manufacture of the motor is complicated by the need to form so many independent motor components, and by the assembly efforts necessary to connect the tank to the plate or engine.
An improved oil reservoir for an outboard motor is desired.